Electromagnetic Interference Shield and Heat Sink Apparatus

ABSTRACT

A combination heat sink and electromagnetic interference shield device is provided for a point of distribution card of a television receiver. The combination POD card heat sink and EMI shield device includes a combined thermal transfer and electromagnetic conduction portion that provides thermal and EM coupling or contact between an enclosure of the POD card and the metal control module enclosure of a television. Configured metalwork of the combination heat sink and EMI shield device provides conduction of heat from the POD card to provide the heat sink and short circuiting of developed currents to provide EMI shielding. The combined thermal transfer and EM conduction portion provides a low impedance connection between the POD card and the surrounding module metalwork of the television. This low impedance path provides a short for circulating current in the exposed metalwork that diminishes or essentially eliminates EMI. The present invention allows a POD card to operate at room temperature without the need for a cooling fan through the heat sink metalwork.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of television receivers and,more particularly, to the use of point of distribution cards intelevision receivers.

2. Background Information

Starting in 2004, regulations require all television receivers(televisions) that want to carry a “Digital Cable Ready” labelindicating that the television receiver is capable of receiving anddecoding various digital cable television formats, must incorporate whatis known as a Point of Distribution (POD) card. A POD card is similar toa smart card or PCMCIA card, such as are used in satellite televisionreceivers and computers. The POD cards allow for as needed updating ofthe encryption that is used in the television receiver to protect thevideo content from unauthorized copying.

Present specifications for POD cards require the capability of handlingtwo (2) separate encoded video paths. The encrypted data passing throughthe POD card is MPEG-2 format and must be decrypted using the decryptionkey in the POD card. Due to the high speed of the data, there can be upto 2.5 watts (W) of power dissipated by the POD card.

Moreover, due to the high speed of data, i.e. several megabytes persecond, the internal clock edges are roughly 1 nanosecond, generatingelectromagnetic interference (EMI) harmonics up to 5 GHz. While this isnot a significant problem for the portion of the POD card enclosed inthe metalwork of the television chassis, an additional problem existswith respect to the unenclosed portion of the POD card as discovered bythe present inventors and shown from various radiation tests.

The classical method of fixing a temperature problem is to either reducethe heat at the source or provide a fan to cool the device. In thepresent case, the 2.5 W dissipation of the POD card is a specificationrequirement. One thought was to use metal PCMCIA rails to help conductthe heat from the POD card to the metal enclosure of the televisionreceiver. The cost of tooling such metal rails, however, is currentlycost prohibitive.

While a fan could be used for cooling the POD card, the maindisadvantage of a fan is the noise. Many televisions are used in placeswhere such fan noise would be considered unacceptable. This isespecially true for when the television is off.

From an EMI standpoint, the standard means of limiting the EMI from aPOD card is to enclose the exposed portion of the card in a metal box.In order for the customer to change the POD card, the customer has toopen the door. In critical applications, an interlock can be provided toensure that the customer closes the door once the POD card is replaced.Although functional, tooling costs and complexity of the door is not anacceptable solution.

It is thus evident from the above discussion that what is needed is amanner of conducting heat from and shielding electromagneticinterference generated by a POD card, particularly, but not necessarily,with respect to or in a television receiver.

This need and others is accomplished through application of theprinciples of the subject invention and/or as embodied in one or morevarious forms and/or structures such as are shown and/or describedherein.

SUMMARY OF THE INVENTION

The invention provides a combination heat sink and electromagneticinterference (EMI) shield for a point of distribution (POD) card.Configured metalwork of the combination heat sink and electromagneticinterference shield provides conduction of heat from the POD card. Thiseliminates the need for a fan at room temperatures. In addition, theconfigured metalwork of the combined heat sink and electromagneticinterference shield provides EMI shielding of a portion of the POD cardthat extends beyond a metal enclosure or wrap of a POD control module(e.g. an HDTV control module).

The present combination POD card heat sink and EMI shield includes acombined thermal transfer and electromagnetic (EM) conduction portionthat provides thermal and EM coupling or contact between an enclosure ofthe POD card and the metal control module enclosure of a television. Thecombined thermal transfer and EM conduction portion provides a lowimpedance connection between the POD card and the surrounding modulemetalwork of the television. This low impedance path provides a shortfor circulating current in the exposed metalwork that diminishes oressentially eliminates EMI.

In one form, there is provided a combination heat sink andelectromagnetic interference shield device for a POD card receptor of atelevision receiver. The device includes a POD card guide portionconfigured to be adjacent a POD card inserted into the POD card receptorof the television receiver, and a combined thermal transfer andelectromagnetic conduction portion extending from the POD card guideportion, the combined thermal transfer and electromagnetic conductionportion providing thermal and electromagnetic coupling between theinserted POD card and metalwork of the television receiver.

According to another form, there is provided a combination heat sink andelectromagnetic interference shield device for a POD card receptor of atelevision receiver. The device includes a first combination heat sinkand electromagnetic interference shield, and a second combination heatsink and electromagnetic interference shield disposed opposite to thefirst combination heat sink and electromagnetic interference shield. Thefirst combination heat sink and electromagnetic interference shield hasa first POD card guide portion configured to be adjacent one side of aPOD card inserted into the POD card receptor of the television receiver,and a first combined thermal transfer and electromagnetic conductionportion extending from the first POD card guide portion and providingthermal and electromagnetic coupling between the inserted POD card andmetalwork of the television receiver. The second combination heat sinkand electromagnetic interference shield has a second POD card guideportion configured to be adjacent another side of the POD card insertedinto the POD card receptor of the television receiver and opposite tothe first POD card guide receptor forming a POD card reception areatherebetween, and a second combined thermal transfer and electromagneticconduction portion extending from the second POD card guide portion andproviding thermal and electromagnetic coupling between the inserted PODcard and metalwork of the television receiver.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a simplified block diagram of an exemplary television receiverhaving a POD module shown in side view, the POD module incorporating acombination heat sink and electromagnetic interference shield assemblyfor a POD card in accordance with the principles of the presentinvention;

FIG. 2 is a perspective view of a combination heat sink andelectromagnetic interference shield of the combination heat sink andelectromagnetic interference shield assembly shown in FIG. 1;

FIG. 3 is a top plan view of the combination heat sink andelectromagnetic interference shield of FIG. 2;

FIG. 4 is a side view of the combination heat sink and electromagneticinterference shield of FIG. 2 taken along line 4-4 of FIG. 2;

FIG. 5 is an end view of the combination heat sink and electromagneticinterference shield of FIG. 2 taken along line 5-5 of FIG. 3 especiallyin relation to a POD card shown therewith;

FIG. 5A is an enlarged view of the POD card and prongs of thecombination heat sink and electromagnetic interference shield takenalong circle 5A of FIG. 5;

FIG. 6 is a sectional view of the combination heat sink andelectromagnetic interference shield of FIG. 2 taken long line 6-6 ofFIG. 3 particularly showing the outer prong thereof, the outer prongillustrated with reference to a manner of mounting, particularly showingthe outer prong with a POD card, printed circuit board and moduleenclosure; and

FIG. 7 is a sectional view of the combination heat sink andelectromagnetic interference shield taken along line 7-7 of FIG. 3particularly showing the inner prong thereof, the inner prongillustrated with reference to an inserted POD card.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the drawings representembodiments of the invention, the drawings are not necessarily to scaleand certain features may be exaggerated in order to better illustrateand explain the invention. The exemplification set out hereinillustrates an embodiment of the invention, but such exemplification isnot to be construed as limiting the scope of the invention in anymanner.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiment disclosed herein is not intended to be exhaustive orlimit the invention to the precise form disclosed so that others skilledin the art may utilize its teaching.

FIG. 1 illustrates an exemplary television receiver, generallydesignated 100. The television receiver 100 represents various types ofdevices that receive and process television signals but is particularlyrepresentative of a television. More particularly, the televisionreceiver 100 is representative of a digital cable-ready television. Itshould be appreciated, however, that the present invention is applicableto all types of television receivers and as well to other electronicdevices that utilize integrated circuit cards such as Point ofDistribution (POD) cards, smart cards, PCMCIA cards, and the like. Itshould be appreciated that the term POD card refers to all types ofintegrated circuit cards and cards comprising electronic circuitry suchas are used in televisions, particularly such as for satisfyingrequirements for providing a digital cable-ready television/televisionreceiver.

With continued reference to FIG. 1, the television 100 includes aprocessor/controller 102 such as is known in the art for operationand/or control of the various components, parts, or portions of thetelevision 100. A controller (processor) 102 is shown that representsthe ability of the television 100 to perform necessary televisionfunctions. Memory 140 is also provided that includes programinstructions 142 for operation of the television 100 as set forthherein. The television 100 also includes other components such as areknown in the art for televisions, but which are not shown, such asmemory for storing operating instructions, data and/or the like.

The television 100 includes a digital television control module 101 suchas an HDTV control module. The digital television control module 101comprises a metal enclosure 104 that may be known as metalwork or awrap. The metalwork 104 is composed of a metal suitable for heatconduction and electromagnetic interference (EMI) shielding. Thetelevision 100 and metalwork 104 include an opening for a POD card 114.

The enclosure 104 houses a printed circuit board (PCB) 116 that carriesvarious circuitry/components for operation of the control module 101.The PCB 116 represents one or more PCBs if desired. A POD card connector118, that may be the same as or similar to a PCMCIA connector, isconnected to the PCB 116 and is adapted, configured to operable toreceive an appropriate end of the card 114. In accordance with theprinciples of the present invention, a combination heat sink and EMIshield component or assembly 106 is situated on or proximate to the PCB116. The combination heat sink and EMI shield 106 forms a card receptor,reception area, holder, receiver, slot, chamber or the like 112. Thecard 114 is thus accommodated by the combination heat sink and EMIshield 106.

The combination heat sink and EMI shield 106 for the card 114 isembodied as two combination heat sink and EMI shield components 108 and110. Each one of which includes a combined thermal transfer andelectromagnetic (EM) conduction portion 122 and 124 respectively, thatprovides thermal and EM coupling or contact between an enclosure of thePOD card and the metal control module enclosure 104 of the television100. Each conduction portion 122 and 124 has a section or portion whichcontacts or thermally and electromagnetically couples with the POD card114 (when received in the channel 112) and a portion of which contactsor thermally and electromagnetically couples with the metalwork 104. Inthis manner, the portions 122 and 124 provide a thermal andelectromagnetic path from the POD card 114 and the metalwork 104. Thecombined thermal transfer and EM conduction portions 122 and 124 providelow impedance connections between the POD card and the surroundingmodule metalwork of the television. This low impedance path provides ashort for circulating current in the exposed metalwork that diminishesor essentially eliminates EMI.

The television 100 is shown including a POD card fan 130 that isconnected to and controlled by the controller 102 in conjunction withthe program instructions 142. A temperature sensor (TS) 132 may also beprovided that is coupled to the PCB 116 and operable to provide ambienttemperature readings. The controller 102 utilizes the temperaturereadings of the temperature sensor 132 to determine if the fan 130should be turned on or off. In accordance with the principles of thepresent invention, the combination heat sink and EMI shield 106 iscapable of adequately dissipating heat from the POD card 114 at oraround room temperatures and thus at room temperatures, the fan 130 isoff. The fan is thus kept off until the room ambient temperature isaround 80° F. The controller 142 is thus operable to turn the fan onwhen ambient temperatures are above room temperature. The instrumentspecification requires that the instrument run to 40° C., so the fan hasto be able to keep the POD case temperature to <65° C. in a 40° C.

Referring to FIGS. 2-7, an exemplary combination heat sink andelectromagnetic interference (EMI) shield device 20 (combination heatsink and EMI shield 20) such as is usable with or as the combinationhead sink and EMI shield assembly 106 of FIG. 1 is depicted. Theexemplary device 20 represents either one of the upper and lowerdevices, members or components 108 and 110 of the combination heat sinkand EMI shield assembly 106 since only one such combination heat sinkand EMI shield device may be sufficient to constitute the combinationheat sink and EMI shield assembly 106, or, and as shown in the preferredembodiment of FIG. 1, with the use of a pair of identical combinationheat sink and EMI shield devices 108 and 110.

The combination heat sink and EMI shield device, component or member 20is characterized by a body 22 that is fabricated from a material thatprovides heat sink properties and EMI shielding properties such as ametal. An exemplary metal may be a phosphor bronze or a berylliumcopper. Other metals or materials may, of course, be utilized. The body22 includes a section 24 that forms a side of the reception area 112.Extending from an end of the section 24 are two angled legs 30 and 32which each terminate in feet 34 and 40 respectively. Foot 34 is definedby a front portion 36 and a rear portion 38. Foot 40 is defined by afront portion 42 and a rear portion 44. As best seen in FIG. 1, a footmay be used to stabilize the combination heat sink and EMI shield deviceon a PCB or otherwise.

Extending from an end of the section 24 opposite the legs 30 and 32 is afirst angled section 26 and a second angled section 28. The secondangled section is configured so as to extend or turn underneath and backaround so as to be somewhat to substantially co-planar with the section24 to define an elongated end tab 46. The elongated end tab 46optionally a first mounting hole 48 at one end thereof, and a secondmounting hole 50 on another end thereof. These mounting holes may beused to attach the device 20 to the PCB 116 either directly or viastandoffs (not shown) typically via screws or other fasteners.

In accordance with the principles of the subject invention, thecombination heat sink and EMI shield device 20 includes a firstcombination thermal transfer and electromagnetic (EM) conduction portion52 and a second combination thermal transfer and electromagnetic (EM)conduction portion 54, each of which provides thermal and EM coupling orcontact between the POD card 114 and the metal control module enclosure104.

The first combination thermal transfer and EM conduction portion 52includes an outer, curved prong 56 and an inner curved prong 58. Thesecond combination thermal transfer and EM conduction portion 54likewise includes an outer, curved prong 66 and an inner curved prong68. Each prong is adapted, configured and/or operable to provide a heatconduction and EM path between the card 114 and the enclosure 104.Particularly, each prong is adapted, configured and/or operable tocontact and thus provide thermal and EM coupling with the enclosure orhousing of the card 114 and with the enclosure 104.

The outer prong 56 of the first combination thermal transfer and EMconduction portion 52 has a card contact portion 60 and an enclosurecontact portion 61. The inner prong 58 of the first combination thermaltransfer and EM conduction portion 52 has a card contact portion 62 andan enclosure contact portion 63. Likewise, the outer prong 66 of thesecond combination thermal transfer and EM conduction portion 54 has acard contact portion 70 and an enclosure contact portion 71, while theinner prong 68 of the second combination thermal transfer and EMconduction portion 54 has a card contact portion 72 and an enclosurecontact portion 73.

FIG. 5 shows a POD card 114 in relation to the combination heat sink andEMI shield device 20 to illustrate the manner in which an inserted PODcard is situated relative to one combination heat sink and EMI shielddevice 20. Referring additionally to FIG. 5A, the current POD card caseconfiguration is shown and particularly with respect to the prongs 56and 58. The POD case includes a narrowed section 126 on both sidesthereof, defining an undersurface 127. The undersurface 127 is adistance Δh from the undersurface 115 of the POD case. As such, theprong 56 is Δh greater in height than the prong 58. It should beappreciated that the same relationships hold for the combination thermaltransfer and EM conduction portion 54. The difference in height of theouter prongs 56 and 66 relative to the inner prongs 58 and 68, createsor defines a channel that guides the POD card due to the configurationof the POD card case.

FIG. 6 particularly shows the configuration of the outer prong 56 of thefirst combination thermal transfer and EM conduction portion 52 as itcontacts the POD card case. It should be appreciated from the above,that the outer prong 66 of the second combination thermal transfer andEM conduction portion 54 has the same configuration. The contact portion60 of the outer prong 56 is configured for contact or coupling with thecard case surface 127 of the portion 126, while the contact portion 61of the outer prong 56 is configured for contact or coupling with themetalwork 104, or other metalwork of the television 100 as appropriate.

Moreover, FIG. 6 shows the structure 46 and prong 56 as mounted to astandoff 120 via a screw 122 or the like. The screw 122 extends throughhole 50 (see FIG. 3) of portion 46. The PCB 116 is also preferablysituated between the portion 46 and the standoff 120. The screw 122 andstandoff 120 are at least thermally conductive (and optionallyelectromagnetically) to aid in heat transfer to the enclosure 104, orEMI as the case may be.

FIG. 7 particularly shows the configuration of the inner prong 58 of thefirst combination thermal transfer and EM conduction portion 52. Itshould be appreciated from the above, that the inner prong 68 of thesecond combination thermal transfer and EM conduction portion 54 has thesame configuration. The contact portion 62 of the inner prong 58 isconfigured for contact or coupling with the card case surface 115, whilethe contact portion 63 of the inner prong 58 is configured for contactor coupling with the metalwork, or other metalwork of the television 100as appropriate (not shown).

It should be further appreciated that the specific configuration ofportions or parts of the combination heat sink and EMI shield device 20may deviate from that which is shown. This includes the configuration ofthe prongs or heat and EM conductors.

While this invention has been described as having a preferred design,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, of adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and that fallwithin the limits of the appended claims.

1. A device comprising: an integrated circuit card guide portionconfigured to be adjacent an integrated circuit card inserted into anintegrated circuit card receptor of the television receiver; and acombined thermal transfer and electromagnetic conduction portionextending from the integrated circuit card guide portion, the combinedthermal transfer and electromagnetic conduction portion providingthermal and electromagnetic coupling between the inserted integratedcircuit card and metalwork of the television receiver.
 2. The device ofclaim 1, wherein the integrated circuit card guide portion and thecombined thermal transfer and electromagnetic conduction portion areformed from a thermally and electromagnetically conductive material. 3.The device of claim 1, wherein the combined thermal transfer andelectromagnetic conduction portion includes a plurality of firstsurfaces configured to contact the integrated circuit card and aplurality of second surfaces configured to contact the metalwork.
 4. Thedevice of claim 1, wherein the combined thermal transfer andelectromagnetic conduction portion comprises a plurality of arcuateprongs defining the plurality of first surfaces configured to contactthe integrated circuit card and the plurality of second surfacesconfigured to contact the metalwork
 5. The device of claim 1, whereinthe combined thermal transfer and electromagnetic conduction portioncomprises: a first side portion defining a first outer prong and a firstinner prong; a second side portion opposite the first side portion anddefining a second outer prong and a second inner prong; the first andsecond outer prongs contacting a first surface of an inserted integratedcircuit card case, and the first and second outer prongs contacting asecond surface of the inserted POD card case.
 6. The device of claim 5,wherein the first and second outer prongs have a greater height than thefirst and second inner prongs.
 7. The device of claim 1, furthercomprising: a pair of legs extending from the integrated circuit cardguide portion opposite to the combined thermal transfer andelectromagnetic conduction portion.
 8. A device comprising: a firstcombination heat sink and electromagnetic interference shield; and asecond combination heat sink and electromagnetic interference shielddisposed opposite to the first combination heat sink and electromagneticinterference shield; the first combination heat sink and electromagneticinterference shield having a first integrated circuit card guide portionconfigured to be adjacent one side of an integrated circuit cardinserted into an integrated circuit card receptor of the televisionreceiver, and a first combined thermal transfer and electromagneticconduction portion extending from the first integrated circuit cardguide portion and providing thermal and electromagnetic coupling betweenthe inserted integrated circuit card and metalwork of the televisionreceiver; and the second combination heat sink and electromagneticinterference shield having a second integrated circuit card guideportion configured to be adjacent another side of the integrated circuitcard inserted into the integrated circuit card receptor of thetelevision receiver and opposite to the first integrated circuit cardguide receptor forming a integrated circuit card reception areatherebetween, and a second combined thermal transfer and electromagneticconduction portion extending from the second integrated circuit cardguide portion and providing thermal and electromagnetic coupling betweenthe inserted integrated circuit card and metalwork of the televisionreceiver.
 9. The device of claim 8, wherein the first and secondcombination heat sink and electromagnetic interference shields aresubstantially identical.
 10. The device of claim 8, wherein the firstand second combination heat sink and electromagnetic interferenceshields is formed of a thermally and electromagnetically conductivematerial.
 11. The device of claim 8, wherein the first and secondcombined thermal transfer and electromagnetic conduction portionsinclude a plurality of first surfaces configured to contact theintegrated circuit card and a plurality of second surfaces configured tocontact the metalwork.
 12. The device of claim 11, wherein the first andsecond combined thermal transfer and electromagnetic conduction portionscomprise a plurality of arcuate prongs defining the first and secondcontact surfaces.
 13. The device of claim 8, wherein: the first combinedthermal transfer and electromagnetic conduction portion includes, afirst outer prong and a first inner prong; and the second combinedthermal transfer and electromagnetic conduction portion includes, asecond outer prong and a second inner prong, wherein the first andsecond outer prongs are adapted to contact a first surface of anintegrated circuit card case, and the first and second outer prongsadapted to contact a second surface of the integrated circuit card case.14. The device of claim 13, wherein the first and second outer prongshave a greater height than the first and second inner prongs.